1. Field of the Invention
The present invention relates generally to microminiature electronic elements and particularly to an improved design and method of manufacturing a multi-connector assembly having noise shielding and internal electronic components.
2. Description of Related Technology
Multi-connector assemblies are well known in the electronic connector arts. As shown in FIGS. 1a-1c, such assemblies 100 typically comprise a number of rows 101 and columns 103 of individual connectors 104 (such as the RJ 11 or RJ 45 type) arranged so as to allow the simultaneous insertion and connection of multiple modular plugs (not shown) into the plug recesses 106 of the connectors. See, also, for example, U.S. Pat. No. 6,193,560 issued Feb. 27, 2001, co-owned by the Assignee hereof. There are several major considerations in designing and manufacturing such a multi-connector assembly, including: (i) shielding the individual connectors against externally generated electromagnetic interference (EMI) or xe2x80x9cnoisexe2x80x9d, (ii) the size or volume consumed by the assembly, (iii) reliability, and (iv) the cost of manufacturing.
With respect to EMI, prior art multi-connector assemblies such as that of FIGS. 1a-1c are typically constructed from a molded plastic housing 102 in which the individual connectors 104 are integrally formed, and an external metallic noise shield 172 which wraps around or envelops much of the external surface area of the connector housing. This approach of using merely an external xe2x80x9cwrap-aroundxe2x80x9d noise shield 172 has several drawbacks, however. Specifically, such an arrangement does not provide complete or even near-complete shielding of the individual connectors 104 in the assembly 100, since the bottom surface 111 of the connector housing is often left largely unshielded due to concerns of reduced reliability due to electrical shorting between the connector conductors 120 and the metallic shield 172. This xe2x80x9cgapxe2x80x9d in the shielding decreases the overall performance of the connector assembly 100 by decreasing the signal-to-noise ratio (SNR) resulting from the increased noise. Additionally, such wrap-around external shields 172 do not address the issue of cross-connector noise leakage; i.e., noise radiated by the components of one connector in the assembly interfering with the signal of the other connectors, and vice-versa.
Accordingly, attempts have been made to provide additional shielding between the individual connectors in the assembly, including providing one or more shield elements between the conductors thereof. See U.S. Pat. No. 5,531,612 entitled xe2x80x9cMulti-port Modular Jack Assemblyxe2x80x9d issued Jul. 2, 1996 (""612 patent). While an improvement over the aforementioned prior art devices using only a xe2x80x9cwrap aroundxe2x80x9d noise shield, the invention of the ""612 patent suffers from several disabilities, including inter alia: (i) no provision for noise shielding between the connector assembly and the substrate (e.g., PCB) to which it is mounted; and (ii) The use of substantially perpendicular molded conductor inserts 140a, 140b or carriers (two per connector) which complicate the manufacture and assembly of the device and increase cost of manufacturing. Additionally, the device disclosed in the ""612 patent does not include filtering, voltage transformation, or other electronic components for each connector integrally within the assembly itself, hence, no provision for physically accommodating and shielding such components is provided.
A related issue concerns the use of noise-emitting sources such as light emitting diodes (LEDs) 160 in the connectors of the assembly; such components are also potentially significant sources of EMI, and therefore should in many cases be shielded from the other connector components in order to achieve optimal performance. Prior art multi-connector assemblies such as that of FIGS. 1a-1c or the ""612 patent typically have no provision for shielding of the LEDs from the other connector assembly components, a significant disability. Rather, the LEDs 160 are commonly disposed physically within the external shield 172, often in close proximity to other connector components such as the conductors 120 and in-line electronic filters (not shown).
Since in general consumers are highly sensitive to the cost and pricing of multi-connector assemblies, there exists a constant tension between producing a multi-connector assembly which has the best possible (noise) performance with the lowest possible cost. Hence, the most desirable situation is that where comprehensive external and cross-component noise shielding can be implemented with little impact on the cost of the finished product as a whole. Additionally, since board space (xe2x80x9cfootprintxe2x80x9d) and volume are such important factors in miniaturized electronic components, improvements in performance and noise shielding ideally should in no way increase the size of the component. Lastly, the connector assembly must also optimally include signal filtering/conditioning components such as inductive reactors (i.e., xe2x80x9cchokexe2x80x9d coils), transformers, and the like with no penalty in terms of space or noise performance.
Based on the foregoing, it would be most desirable to provide an improved multi-connector assembly and method of manufacturing the same. Such an improved assembly would be reliable, and provide enhanced external and intra-connector noise suppression, including suppressing noise between integral electronic components and the substrate to which the assembly is mounted, while occupying a minimum volume. Additionally, such improved device could be manufactured easily and cost-efficiently.
The present invention satisfies the aforementioned needs by providing an improved shielded multi-connector assembly, and method of manufacturing the same.
In a first aspect of the invention, an improved shielded connector assembly for use on, inter alia, a printed circuit board or other electronic substrate is disclosed. In one exemplary embodiment, the assembly comprises a connector housing having a plurality of connector recesses; a plurality of conductors disposed within each of the plurality of recesses; and a shielded substrate disposed relative to the connector housing and providing shielding there for. The connector housing is formed from a non-conductive polymer and comprises multiple rows of individual RJ45 or RJ11 connectors, each having a plurality of conductors adapted to mate with the corresponding conductors of a modular plug received within the respective recesses. The conductors of each individual connector are formed so as to obviate the need for overmolded carriers, and are disposed on a removable electronic component package. The terminal end of the conductors penetrates the shielded substrate disposed on the bottom of the connector housing, the substrate being a multi-layered device specially constructed to provide shielding against electromagnetic interference (EMI) or other deleterious electronic noise. The substrate further acts to help register the terminal ends of the conductors to facilitate rapid and easy connection to an external component. An external noise shield is also installed to shield against electronic noise transmitted via surfaces other than the bottom of the housing. In a second embodiment, the shielded substrate comprises a single-layer copper alloy shield which is shaped to cover the majority of surface area on the bottom of the connector.
In a second embodiment, the connector assembly further includes a top-to-bottom shield element disposed substantially between the horizontal rows of connectors, the top-to-bottom shield providing noise separation between the conductors of the connectors in each row. In one variant, the top-to-bottom shield element comprises a removable metallic strip which is received within a preformed groove existing between the rows of individual connectors. In another variant, the top-to-bottom shield is formed as a thin metallic film within the connector housing during fabrication. The assembly further includes individual front-to-back shielding elements disposed between the electronic component packages of each individual connector, the front-to-back shielding elements providing noise separation between the electronic components within each adjacent package. In one variant the front-to-back shielding elements comprise a copper alloy insert which is held in place between the component packages of the first and second row connectors. In another variant, the shielding elements comprise a thin copper film which is deposited on the back of the first row component package.
In a third embodiment, the assembly further includes a plurality of light sources (e.g., light-emitting diodes, or LEDs) adapted for viewing by an operator during operation. The light sources advantageously permit the operator to determine the status of each of the individual connectors simply by viewing the front of the assembly. Optional shielding proximate to the LEDs for suppressing noise emitted by the LEDs is also disclosed.
In a second aspect of the invention, an improved electronic assembly utilizing the aforementioned connector assembly is disclosed. In one exemplary embodiment, the electronic assembly comprises the foregoing shielded connector assembly which is mounted to a printed circuit board (PCB) substrate having a plurality of conductive traces formed thereon, and bonded thereto using a soldering process, thereby forming a conductive pathway from the traces through the conductors of the respective connectors of the package. In another embodiment, the connector assembly is mounted on an intermediary substrate, the latter being mounted to a PCB or other component using a reduced footprint terminal array.
In a third aspect of the invention, an improved method of manufacturing the connector assembly of the present invention is disclosed. The method generally comprises the steps of forming an assembly housing having a plurality of modular plug recesses disposed therein, the recesses being formed in at least first and second rows; providing a plurality of conductors comprising a first set adapted for use with the first row of connectors within the housing element, and a second set adapted for use with the second row; forming the end of the conductors to be received within the aforementioned plug recesses so as to mate with corresponding conductors of a modular plug; providing a shielded substrate and an external shield; installing the first set of conductors in the first row of connectors in the housing element; installing the second set of conductors in the second row of connectors in the housing element; installing the shielded substrate on one side of the housing element; and installing the outer shield around at least a portion of the remaining exposed sides of the housing element. In one embodiment, the connectors comprise RJ11 connectors, and the method further comprises providing at least one electrical component (e.g., filter or choke coil) in the conductive pathway of at least one of the sets of conductors in order to condition the signal passed via the conductors. The external shield is also soldered to various points on the shielded substrate so as to add rigidity to the assembly. In another embodiment, the method further comprises providing a top-to-bottom shield and a plurality of front-to-back shield elements; installing the top-to-bottom shield between the first and second rows of connectors; installing the front-to-back shield elements between the electronic components present in the conductive pathways of the various connectors; and bonding the front to-back shield elements to the top-to-bottom shield element, and the top-to-bottom shield element to the external shield.